Affinity chromatography is a method that takes advantage of the interaction between a molecule on the chromatography matrix and a binding partner for the molecule in order to select a subpopulation of binding partners from a larger pool of substances with varying affinity to the molecule or from a crude mixture, such as a fermentation stock.
Methods, such as affinity chromatography, that utilizes binding between molecules for the purpose of purification, analysis, diagnostics, etc are inherently limited by steric hindrance caused by the orientation of the molecule on the chromatoghraphy matrix and by the way it is coupled to a matrix (via a carrier molecule, a spacer, a linker etc). A consequence of this is that only a limited part of the molecule's total set of discrete binding sites is exposed to the receptor—those used for coupling to the matrix are not accessible to the binding partners which are brought into contact with the coated chromatography matrix.
In many cases, this does not present a problem, since only one particular binding characteristic of the binding partner is of interest.
When developing receptors, either so-called natural receptors such as antibodies, or synthetic receptors such as Molecular Imprinted Polymers (MIPs), selection/isolation of the best binding individual receptor entities—antibody molecules or MIP particles, either soluble or insoluble—is a means of improving the affinity, specificity, capacity etc of the resulting receptor based product—in relation to MIPs, cf. WO 2007/095949 where purification methods are disclosed which give rise to MIP compositions having improved binding affinity and capacity for a target molecule.
There is, however, a need to further improve the binding characteristics of compositions such as MIPs and polyclonal antibodies.